Q50. The letters of the word "INCOMPREHENSIBILITIES" are arranged alphabetically in reverse order. How many positions of the letter/letters will remain unchanged?

The given word is INCOMPREHENSIBILITIES. First, list all the letters and their counts: I (5), N (2), C (1), O (1), M (1), P (1), R (1), E (3), H (1), B (1), L (1), S (2), T (1). Total letters: 21.

Now, arrange these letters alphabetically in reverse order (from Z to A): T S S R P O N N M L I I I I I H E E E C B. Let's compare the original word with the reverse alphabetically sorted sequence, position by position: Original: I N C O M P R E H E N S I B I L I T I E S Position: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Sorted: T S S R P O N N M L I I I I I H E E E C B Comparing the letters at each position, we find matches at: - Position 13: Original 'I', Sorted 'I'.

(Match) - Position 15: Original 'I', Sorted 'I'. (Match) All other positions have different letters. Therefore, exactly two positions of the letters remain unchanged. This question tests attention to detail and systematic comparison, a common type of logical reasoning problem in CSAT.